Method and apparatus for simultaneous heat and mass transfer

ABSTRACT

A method and apparatus for heat and mass transfer is described that is applicable to: concentration, crystallization, purification, fractionation, stripping, absorption, and/or heat exchange for liquid media; drying for solid or gel media; and temperature and humidity modification for gas media. Generally, using a moving gas, such as air at a constant and atmospheric pressure, a continual change in a vapor-liquid equilibrium is created between proximate but continually changing gas and liquid temperatures within energy transferring chambers. Chamber wetting, implemented segmentedly, allows mass transfer into and from the moving gas. A forced temperature differential in each chamber causes heat transfer between chambers by means of thermally conductive partitions. This transfer can allow condensation causing further evaporation in the opposite chamber resulting in a recycling of energy. Concurrent with temperature variances, the segmented wetting can further allow wetting substance concentrations caused by evaporation, selective condensation, or absorption to vary between wetted sectors. A migratory movement connecting these wetted sectors generally provides for development of applicable concentration gradients between the wetted sectors along the chamber length.

BACKGROUND OF THE INVENTION

The present invention relates to a method and apparatus for efficientheat and mass transfer. More particularly, the present invention relatesto a method and apparatus incorporating chambers and heat transferringpartitions with segmented wetting that operates with a single gas streamat nearly constant pressure. The segmented wetting of part or all ofthese chambers allows gas and wetting substance temperatures to beproximate and evaporating and condensing liquid temperature andconcentration integrities to be maintained. A migration movement ofthese wetting substances from segment to segment may allow temperatureand concentration gradients to be developed or maintained. The methodand apparatus can be utilized as a liquid phase concentrator, acrystallizer, a purifier, a fractionator, a stripper, an absorber, aheat exchanger, a solids or gel dryer, a reactor, and as a gas cooler orheater, and can be coupled to other processes.

Earlier developments which included elements such as a moving gas havingchanging vapor carrying capability, or a wetted heat transferringpartition, provide a background for the present invention. Apparatus andmethods using a moving gas at substantially constant pressure are known.For example, U.S. Pat. Nos. 3,860,492 to Lowi, et al. and No. 4,363,703to ElDifrawi, et al. teach humidification-dehumidifications inindependent vessels where energy savings, generally, relate to raisingincoming feed liquid temperature. U.S. Pat. No. 3,356,591 to Petersonalters process air pressures first by compressing and heating ambientair for evaporations and then a turbine to expand and cool the air forcondensation. In U.S. Pat. No. 3,214,351, Lichtenstein shows that theprocess can allow for air recirculation in a closed system under vacuumconditions. In other closed systems, Ramsmark discloses in U.S. Pat. No.4,243,526, an internal combustion engine driving a compressor with thefirst providing heat and the second a means for condensing while Grees,U.S. Pat. No. 4,310,282 teaches using the opposite sides of a heat pumpfor temperature differentials. Other closed systems have incorporatedmethods for causing the recirculating air to be of higher pressure andtemperature in the evaporation vessel than in the condensation vessel.In creating these differentials, Rhoades, in U.S. Pat. No. 4,200,497,describes using a high pressure water jet and a low pressure condenser,Mock, in U.S. Pat. No. 4,276,124 describes combining a fan followed by apressure regulator, while Pampel, U.S. Pat. No. 4,308,111 incorporates amembrane between the two functions. U.S. Pat. Nos. 3,167,488 by Malekand No. 4,329,205 by Tsumara, et al. teach devices without forced gasmovement where transfer of condensation heat for further evaporation isprovided through a succession of plates each operating at a lowertemperature. An effort to obtain improved mass transfer by negating theeffects of a stagnant gas has been made by Petrik, et al. in U.S. Pat.Nos. 4,329,204 and 4,402,793 by closer spacing of the parallel plates.Use of closely spaced plates is also taught by Henderyckx in U.S. Pat.No. 3,563,860 where vapors through a permeable membrane condense on awall transmitting heat to a liquid increasing its temperature. Acounter-current flow of liquid and vapor is described by Cantrell inU.S. Pat. No. 3,788,954 for separating fluids having different vaporpressures. The use of a plurality of coaxially superimposed liquidcontaining basins in lieu of plates is taught in U.S. Pat. No. 3,930,958by Maruichi. The combination of a gas and a partition in a deviceoperating at constant pressure is shown in U.S. Pat. No. 2,902,114 bySchmerzler wherein two separate air streams are utilized in separatehumidification, heat exchange, and condenser functions. A distilationapparatus having chambers where liquid is evaporated and chambers ordevices on which saturated air is condensed is taught in U.S. Pat. No.3,522,151, by Dinsmore. A nonsegmented wetted heat transfer surfaceallowing liquid mixing is taught in U.S. Pat. No. 4,350,570 byMaisotsenko, et al. in an apparatus wherein a air stream of generallylow humidity is divided into primary and secondary flows with oneserving to cool a separate condensation element. A nonsegmented wettedheat transfer partition adjacent to a generally packed column utilizinga single gas stream wherein gas and liquid streams flow in a concurrentmanner mixing temperature profiles is taught in U.S. Pat. No. 3,822,192by Brown.

It will be apparent that no concerted effort in developing closetemperature approaches of the gas streams, preservation of liquidtemperatures and concentration profiles, and combining these features inan efficient energy and mass transfer method has been contemplated.

In accordance with the present invention, a transfer method and deviceare provided wherein all phases, liquid or gas, may operate thermallycounter-currently, wherein all liquids and gases in close proximity canbe maintained at relative close temperatures, and wherein concentrationsare acheived by maintaining process integrity.

It is an advantage of the present invention that it can operate with aplurality of heat sources. These heat sources can include high gradeheat such as steam or combustion of natural gas, or low grade heat, suchas waste heat, solar energy, and surface heat of water bodies or evenambient air, and the compression of gases to provide the desiredtemperature increases.

It will be appreciated that costs can be quite low. The amount of heatused is minimized because the present invention can reuse this heat manytimes. The invention generally operates at ambient pressure, eliminatingthe high initial costs and maintenance associated with pressure orvacuum vessels. In addition, the heat transfer partitions can be made ofinexpensive plastic film or metal foils.

The apparatus and method of the present invention can be combined withother processes. Examples include efficient reduction of salt solutionsto higher concentrations such as lithium bromide reconcentration in airconditioning systems. Also, separating ammonia-water streams bystripping and vapor absorption may find application in absorptionrefrigeration systems. Coupling its separation capabilities in closedcycle arrangement with reverse electrodialysis, pressure retardedosmosis, or vapor pressure differntial techniques offers a choice ofsolutions beyond the salt brine and water mixtures presentlyinvestigated to include a number of less volatile with more volatilesolution combinations.

It is a further achievement that the present invention requires onlyminor alteration to perform a plurality of applications. For example,many applications were tested in a single laboratory model. In thismodel, performance factors of over 8 were achieved for desalination ofbrackish or sea water. Based on this data, simulations indicateperformance factors ranging in excess of 40 are possible. The model alsoachieved reduction of sea water to almost crystalline condition, and areduction of a potassium carbonate solutions to fifty percent fromtwenty-five percent concentration. The same laboratory model enriched anethanol water mixture with a 10% feed to a 41% concentrate using 1,300Btu's per gallon compared with approximately 6,000 for standarddistillation techniques. Simulation of full scale devices indicate a 10%ethanol solution may be enriched to 95% while offering a 30 times energyreduction compared with conventional distillation columns. In airmanagement applications, the same model offered a 27 percent greaterreduction in air temperature then did a conventional evaporative cooler.In another test, the model, when supplied with a 50% potassium carbonatesolution as a liquid desiccant, reduced a saturated air stream to 56%relative humidity. Simulations indicate achieving dwelling comfort zonemaintenance for the weather conditions of Phoenix, Arizona and Houston,Texas while achieving projected electrical coefficients of performancesranging from 23 to 43.

SUMMARY OF THE INVENTION

The present invention relates to a method of heat transfer and masstransfer. As used herein, heat transfer is the movement of energy thatheats or cools a fluid (liquid or gas) or evaporates a liquid orcondenses a vapor that must exchange through a gas/liquid, gas/solid, orliquid/solid interface or combinations thereof. Mass transfer is themovement of an evaporating liquid from the liquid phase into the gasphase or movement of the condensing vapor from the gas phase into theliquid phase.

The present invention employs a gas which is generally defined as anoncondensing vapor or gas and in most cases is ambient air. This gasgenerally flows through a first chamber and then through a secondchamber, the chambers being thermally connected. Thermally connected, inthis context, means that fluids (gas or liquid) from each chamber andbrought into mutual close proximity on opposite sides of a heattransferring partition so that heat can transfer from one chamber to theother chamber. In its passage, the gas generally operates under nearlyconstant pressure with pressure change caused by frictional losses. Atemperature change by a separate auxiliary heat exchange is affected tothis gas after its passage through the first chamber, but before itsflow through the second chamber. This temperature change has twoeffects. First, it causes a temperature differential to be developedbetween the gases in the chambers. Second, it causes a temperature rangeto be created to this gas from one end of the chamber to the other.These changes cause the gases to approach a vapor-liquid equilibriumvalue and thus receptive to receiving or losing vapors. Equilibriumvalue is a vapor-liquid equilibrium concentration or temperature. Avapor liquid equilibrium can be said to exist when the escape tendencyof the species from liquid to a vapor phase is exactly balanced with theescape tendency of that species from a vapor to a liquid phase at thesame temperature and pressure.

Wetting substances are applied to part or to all of one or bothchambers. The wetting substance may be a liquid, gel, or solid and isgenerally inert. In some cases, the wetting substance can be reactive,meaning that its molecules may be chemically combined with each other orwith the gas. This wetting application is segmented, which means: (1)that the chamber is segmented along its length into sequential sectorsthat may be equal or unequal in width; (2) that uncontrolled mixing ofwetting substances is minimized between sectors; (3) that the wettedsectors of the first and second chambers are sequentially ordered sothat heat transfer between the first and the second chambers will occurin a manner so as to continually change the temperatures of thesegmented wetting substances in one direction along the chamber lengths;and (4) that while wetting a sector, which also includes its heatexchanging partition area, the bulk of the wetting substances remainwithin a sector a required time duration for: (a) their temperature tofollow the temperature of the gas within that sector and/or thetemperature of another segmented wetting of a second chamber sectorthermally connected to the first chamber sector and/or the temperatureof the gas thermally connected to that chamber sector; and (b) apredetermined level of evaporation or condensation to occur into or fromany present gas stream as induced by the vapor-liquid equilibriumimbalance associated with the gas and the wetting substance.

Migratory movement of the wetting substance for a plurality of sectorscan be provided. This migratory movement means: (1) the actual movementof the wetting substance into and out of a sector where the wettingsubstance when exiting a wetted sector has at least one selectedproperty that is different than the same selected property when thewetting substance entered the wetted sector, where a selected propertyis the temperature or the concentration of a wetting substance; and (2)that some portion of the wetting substances of a wetting sector exitsthat sector to enter an adjacent wetting sector. This migratory movementbetween sectors allows a wetting substance property of one sector toinfluence the same property of an adjacent sector, this sequence beingrepeated throughout a plurality of wetted sectors obtaining at least oneoverall directional movement of these wetting substances combined withsequential change in at least one selected property. Migratory movementrate is controlled by addition to or subtraction from the chamberwetting substances by any means causing the required time duration ofthe wetting substance within a wetting sector to be achieved.

In operation, where there is evaporation from these wetting substancesinto the gas stream or selective condensation from this gas stream,segmented wetting coupled with migratory movement provide the followingoccurrences. First, as a sector is wetted by primarily the same wettingsubstances, the now localized wetting substance properties can be forcedto change. Second, as the migratory movement is from one sector toanother, the concentration of one sector influences the wettingsubstance composition of the subsequent sector where it again may bealtered by evaporation or condensation. In this manner, selectedsubstance property gradients can be developed and maintained throughoutthe chamber length. For example, a brackish water feed can be introducedat a chamber end, establishing because of evaporation and migratorymovement a continually higher concentration in each adjacent sector, andcan be extracted as brine or crystals. The condensate, collected in theother chamber, would be purified water.

The apparatus for carrying out the invention generally consists of atleast a first and a second chamber. A gas is moved into the firstchambers by mechanical means which can be a low pressure blower. Mostoften the gas flows of these first chambers and then of the secondchambers are substantially counter-current. Multiple liquid segmentsgenerally caused by segregated pumping and distribution means areprovided. This distribution generally encompasses wetting of the heatexchanging partitions, but may further include wetting methods toincrease chamber gas and wetting substance contact area, for example,the use of droplet sprays or incorporation of packing. The number ofsegmentations is sufficient to allow the wetting substance temperatureto approach the temperatures of the passing gas proximate thereto andalso preserve any significant concentration variances developed withinthese wetting substances. Provision for migration movement of thesewetting substances in most cases from sector to sector over the lengthof the chamber can normally be by basins contained within the chamber.The chambers are thermally connected by heat transferring partitionswhich are exposed on opposite sides to fluids of the first and secondchambers. These fluids always consist of a segmented wetting substanceof one chamber while the fluids of the other chamber further include aliquid resulting from condensation of a gas stream. The partitions,usually of plastic film or metal sheet, generally provide a commonboundary between the first and second chambers, but on occasion may belocated externally to the chambers. Flexibility of partition location islimited by the degree of sector wetting. Referring to the above brackishwater concentration example, the chamber providing for evaporation wouldbe segmentedly wetted generally throughout its length while thecondensation chamber may be optionally segmentedly wetted. If notsegmentedly wetted, the condensation heat released from an everdescending gas temperature throughout the chamber length transfersthrough a heat transmitting partition forming a common boundary with theevaporation chamber. In the event that the condensation chamber issegmentedly wetted, the condensation heat transfers to the wettingsubstances of that chamber. The heat transferring partition may then beat least partially separate from the chambers with sector heat transferaccomplished by the wetting substances of the respective chambers. Inapplications where one chamber heat transferring fluid is a gas, thepartition is physically located between the two chambers in direct heattransfer. External temperature changes are primarily created byauxiliary heat exchange from a multitude of supplies to the gasgenerally after it leaves the first chambers, but before it enters thesecond chambers. In some functions, the gas can be recycled to create aclosed system wherein this gas can be air or other noncondensing gassuch as helium, nitrogen or argon. While the gas is generally inert, insome cases the gas may be reactive, for example nitrogen, hydrogen orchlorine.

The invention can be presented in terms of heat transfer and mass andenergy balances. The conduction of energies between chambers alwaysinvolves sensible heat and, generally, at least one latent heat transferrelated to evaporation or condensation. Sensible heat is that heatrequired to change the temperature of a substance without changing thestate of the substance. Latent heat is that heat required to change thestate of the substance from solid to liquid or from liquid to gaswithout change of temperature or pressure.

A basic heat transfer is established by the auxiliary heat exchange tothe gas before this gas returns to the second chamber. This exchangecauses a temperature differential between the gas in each chamber. Inorder to preserve this temperature differential along the chamberlengths, the gases are made to flow in a thermally counter-currentdirection in the first and second chambers. This thermallycounter-current gas movement results from the thermal connection betweenthe sequentially ordered sectors of the first and second chambers bymeans of the heat transferring partitions.

The continually changing temperatures of the gas within the chamberscause a continual shifting of the vapor-liquid equilibrium value betweenthe liquid and gas phases. This shifting allows evaporation and/orcondensation between the moving gas and the wetting substances. Theenergies released in condensation are normally transferred to the otherchamber allowing for additional evaporation to occur from the wettingsubstances. Where many sectors are wetted, as in the case of theconcentration and fractionation modes of the invention, these transfersof latent energy are many times the sensible energy related to thetemperature change of the gas. This sensible exchange, in turn, isgreater than any auxiliary heat exchange into the gas. In otheroperating modes, for example, air cooling, the latent energiesassociated with evaporation from the segmented wetting substances can beturned to sensible energies in that such evaporation can cause the gasto further lower in temperature.

Generally speaking, minimum wetting substance movement occurs whenenergy transfer between chambers involves exchange directly throughwetted partitions separating the chambers. However, there are occasionswhen this minimum is balanced against other rates. One concern is therate of energy conducting through a certain partition area includingliquids on the partition, called the partition heat transfer flux. Thepartition heat transfer flux is maximized if the temperature differenceacross the partition is increased to a maximum value of the specifiedtemperature differential between chambers. If a chamber partitionoperates below its maximum heat transfer flux capability, this fluxoften can be increased by augmenting adjacent latent energy transferwhich transfers through the partition as sensible energy. Thisaugmentation involves inclusion of additional gas/liquid heat transfercontact area beyond that supplied by wetting the partition, for example,by the use of spray droplets within the chamber area. This expansion oflatent transfer surface, for instance, has been found useful in the gascooling and heating modes of the invention. Conversely, in other casessuch as some concentration operations of the invention, latent transferwithin the chambers is capable of being in excess of the maximumpartition flux. When both chambers are segmentedly wetted, an increasedpartition area can be supplied by thermally connected partitions thatare external to the chambers. In this manner, the partition heattransfer flux can operate at its maximum along with increased chambersensible and latent heat transfer.

For most applications, the above transfers can be understood by viewingtwo mass and energy balances: an external overall balance encompassingthe entire process, and an internal balance around a chamber. A netoverall mass and energy balance encompassing the entire process includesthe enthalpy of the incoming gas plus the input energy to this gas froman auxiliary heat exchange all being equal to the enthalpy of theexiting gas. In some modes of operation, there is also the enthalpy of afeed material and the enthalpy of a product material, as for example inconcentration which may involve an incoming brackish water and productsof substantially pure water and brine concentrate. However, due tofeed/product heat exchange capability or injection/withdraw of thesematerials where they have no significant energy effect, the energyassociated with these feeds and products tends to either cancel or bemade inconsequential. The above energy balance reveals that where bothgas streams are saturated and the auxiliary heat exchange adds energy,for example in the concentration and fractionation modes of theinvention, there would be a shift in temperature of those gas streams inthe same direction as the shift in enthalpies. In this way the gasstream with the highest enthalpy (and highest temperature) would beassociated with the cooling or condensing chamber allowing its energy tobe transmitted to the lower enthalpy (and lower temperature) gas streamlocated in the heating or evaporation chamber and thereby reused. In theair cooling mode of the invention, the same enthalpy relationships areevident. An entering hot unsaturated ambient air remains unsaturated inthe first chamber and receives energy from a dwelling or storage spacebut then remains saturated throughout the second chamber. Owing to thedifferences in saturation, there can be a shift in temperature of thosegas streams in the opposite direction as the shift in enthalpies. Thegas stream with the lowest enthalpy (but highest temperature) would beassociated with the cooling chamber allowing its energy to betransmitted to the higher enthalpy (but lower temperature) gas streamlocated in the second chamber. In summary, the external balanceestablishes the net enthalpy offset and therefore the temperaturedifference between the two chambers and the net amount of liquid thatmay be evaporated or condensed. An internal chamber energy balance givesdetail on the actual amount of temperature rise or fall in a chamber andon the actual amount of liquid evaporated or condensed in a chamber.

An internal mass and energy balance around a chamber equates theincoming gas enthalpy to a chamber plus the conducting energiesassociated with the partition to the exiting gas enthalpy from achamber. The two forms of conducting energies are; (1) sensible energyneeded to heat up or cool down chamber gas, and (2) latent energy neededfor evaporation or condensation into or out of the chamber gas. Theinternal chamber balance also relates the chamber exiting gastemperatures (enthalpy) to the amount of sensible and latent energiesthat can transfer to the gas in a chamber. The more energies that cantransmit to the chamber gas the larger will be the temperature rise andfall and actual evaporation into or actual condensation out of thechamber gas from the chamber entrance to chamber exit.

For any adjacent chambers, the sum of the sensible and latent energiestranferred through the heat exchanging partition tends to cancelalthough the amounts of sensible or latent exchange may vary on eachpartition side. Owing to this cancellation, the net energy balance forthe two chambers or for that matter all chamber sets (the enthalpies oftheir entering and exiting gases) plus the auxiliary heat exchange againgives the net overall mass and energy balance encompassing the entireprocess.

These and other features of the present invention will be understoodupon reading of the following description along with the Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view, with portions broken away, of a device accordingto the present invention with an auxiliary heat exchanger unit, optionalsupplemental gas cooler and gas movement shown schematically:

FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1 withportions shown schematically;

FIG. 3 is a cross sectional view of an alternative positioned device ofthe present invention oriented horizontally;

FIG. 4A is a cross sectional view of a device of the present inventionschematically showing an alternate chamber configuration with separatelycontained heat exchanging partitions.

FIG. 4B is a perspective view, with portions broken away, of thealternate chamber configuration and separately contained heat exchangingpartitions of FIG. 4A.

FIG. 5 is a horizontal sectional view, with portions broken away, of aparalleling and cascading group of devices of the present invention withauxiliary heater and gas movement unit shown schematically;

FIG. 6 is a horizontal sectional view, with portions broken away andportions shown schematically, of a device of the present inventionshowing vapor absorption adjustments;

FIG. 7 is a vertical sectional view, with portions broken away, of adevice of the present invention configured as a solids or gel dryer withan auxiliary heat exchanger unit, optional supplementary cooler and gasmovement unit shown schematically;

FIG. 8 is a perspective view of an alternative multiple channel deviceof the present invention.

FIG. 9 is a horizontal sectional view taken along line 9--9 in FIG. 8;

FIG. 10 is a vertical sectional view taken along line 10--10 in FIG. 8;

FIG. 11 is a horizontal sectional view taken along line 11--11 in FIG.8;

FIG. 12 is a vertical sectional view of FIG. 8 taken along lines 12--12of FIG. 9;

FIG. 13 is a sectional view analogous to FIG. 12 taken along line 13--13of FIG. 11.

FIG. 14 is a schematic view of a device of the present invention coupledwith a reverse electrodialysis power device;

FIG. 15 is a schematic view of a device of the present invention coupledwith a pressure retarded osmosis power generation device;

FIG. 16 is a schematic view of a device of the present invention coupledwith a vapor pressure differential power generation device.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1 and 2, a device of the present invention isshown and generally indicated by the numeral 14 along with auxiliaryheat exchanger unit 15 and optional gas cooler 16 and gas movement unit17, with gas movement shown by ducts 18. Device 14 is shown as arectangular parallelepiped having side walls 19 and 20, end walls 22 and24, top wall 26 and bottom wall 28 with these walls usually insulatedwith insulation 30. As schematically shown, partition 32 separatesdevice 14 into two chambers: chamber 34 which in most applicationsserves for evaporation, and chamber 36 which normally allows forcondensation. In this configuration, these walls and partition aregenerally oriented vertically or nearly so although units withhorizontal or inclined orientation as well as with curved surfaces orshapes where one channel may be a series of tubes can be acceptable. Thelength of these chambers normally ranges from under 2 to 12 meters andfrom less than 1 meter in height to a limit largely dictated by materialavailability of between 2 and 3 meters. The width of each of chambers 34and 36 is shown somewhat disproportionately in the drawings for clarity,the chambers previously constructed have widths varying from 3 mm to 15cm, although other widths may be used. Chamber length, height, and widthdimensions are generally consistent throughout any device 14 althoughthey may vary. For example, chamber 34 may have a different width thanchamber 36, all chambers 34 or 36 may not have the same width, and theheight or width dimensions of the channels may be different along theirlength. Partition 32 serves as a heat conducting surface and preferablyis a mechanically coherent sheet selected from the group of plastics,metals, inorganic glasses or their components. One suitable sheet ofoperating temperatures approaches 85 degree C. is a plastic filmconsisting of a woven web or low density polyethylene laminated on bothsides with polyethylene film which has been made wettable by a treatmentreducing its surface tension on at least one exposed side. A secondsheet suitable for moderate and higher operating temperatures is anannealed cold-rolled stainless steel foil. In higher pressureapplications and in cases where the pressures are significantlydissimilar on each partition side, more sturdy materials includingstainless steel sheet would be used. In some cases, the partitionsurface may be further treated, for example, by the surface depositionof a catalytic material such as platinum metal or iron oxides, where thegases may be reactive with themselves or with the wetting substance. Thewall structure may assist in maintaining the width dimension of chambers34 and 36 through use of attached spacers which offer little restrictionto gas or liquid flow, or by utilization of a rough textured material orone where "dimples" are formed during its fabrication. Insulation of asmall portion of either side of partition 32 may be desirable and suchinsulation 38 shown within chamber 36 may be any efficient and highlyvapor and liquid resistant material or they may serve as a catalyticmaterial.

Containers displayed here as basins 40 and 42 are utilized for liquidspresent in respective chambers 34 and 36. Inlet 44 is provided for feedliquids and is generally located at a point where the temperature andcomposition of a feed material closely approximate the liquidtemperature and composition in basin 40. In applications where a liquidproduct is produced, a heat exchange between basin and feed liquids ispreferred as a means to maximize the energy efficiency of the device.

In certain desalination cases, for example, such heat exchange mayincrease the performance factor by 30%. With internal feed liquid heatexchange, the feed liquid entering via port 44 passes through conduit 46which is shown located such that heat transfer may take place betweenthe liquid contained within and the liquids of basins 40 and 42. Heattransfer may also take place in an external heat exchanger where liquidsare removed from basins 40 or 42, or both basins, and heat exchangedwith an external conduit 46 using any suitable liquid-to-liquid heatexchange equipment. The liquids may be segmentally withdrawn from basins40 or 42 to this heat exchange unit and returned thereto in order topreserve liquid temperature and concentration profiles within respectivebasins. Alternatively, in devices containing a plurality of chambers,one or more chambers may be sealed and converted to feed liquid heatingwherein the feed liquid entering a basin 40 segmentally wets thepartition in the manner described below and receives energy throughpartition 32. Following any of these alternatives, conduit 46 may thenconnect with auxiliary heat exchange unit 15 to supply liquid forevaporation and that liquid portion not evaporated returned to basin 40via entry 48. Basin 40 has a discharge port 50 for removal of liquidtherefrom while basin 42 has discharge port 52 for removal of liquidtherefrom. Multiple ports 50 or 52 may be employed at differentlocations along basins 40 and 42 if the addition or removal of liquidsof varying concentrations or temperatures is desired. Condensate can beremoved from cooling device 14 at discharge 54 where optionalsupplemental cooling device 16 is employed or if liquid scrubbing toremove vapors from the exiting gas is utilized.

Partition 32 may be wetted on side 56 facing chamber 34 and on side 58facing chamber 36 by alternate means that allow temperature variances ofthe wetting liquids and composition differences within these wettingliquids to be segmented along the partition. The preferred segmentedwetting means relies upon the division of the partition length into manysectors indicated by the numeral 60 where the mixing of liquids betweenthese sectors on partition 32 does not occur to any appreciable extent.Partition wetting within each sector may be accomplished by variousmeans. Liquid 62 can be removed from basin 40 via port shown generallyby the numeral 63 and returned to the top of chamber 34 via pump 64 andport 65 where it is discharged to side 56 of partition 32 throughdistribution means 66 which is shown here as a perforated plate inlength equal to sector 60 and terminated by blockages 67. A plurality ofthese pumping and distribution apparati having their basin dischargeports 63 located as 63A through 63E centered within their sector 60, forexample, may provide a full partition wetting but maintain liquidtemperature and applicable concentration integrity through the length ofbasin 40. However, as flow of liquid 62 within basin 40 is possible,some migratory movement from inlet 48 to discharge 50 may transpire orthe migration can be in the opposite direction, for example, an inflowat port 50 and an exit at port 48. In the same manner, liquid 70, can beremoved from basin 42 through port 71 and returned to the top of chamber34 via hydrodynamic modulator 72 through port 73. Discharge side 58 ofpartition 32 is through distribution means 74 which is shown as a spraynozzle. A plurality of these distribution apparati each spraying asector area with discharge ports 71A through 71E centered in theirrespective sector 60 allow basin liquid integrity. As the flow of liquid70 is not restricted, some migratory movement to discharge 52, may takeplace.

In operation, hydrodynamic modulator 72, an alternative to individualpumps 64, when at rest receives basin liquid 70 through check valve 23.On a periodic basis a primary working fluid, which is generally an inertgas such as air or may be a liquid, is injected into hydrodynamicmodulator 72 at port 21. This pressurized primary working fluid causesclosing of check valve 23 and displacement of liquids from hydrodynamicmodulator 72 through port 73. Following release of this pressureoptional check valve 25 closes, check valve 23 opens, and the primaryworking fluid is released via port 21 thereby again allowing basinliquid 70 to enter hydrodynamic modulator 72. This cycle may be repeatedover various time intervals with satisfactory partition wetting, forexample, developed at a frequency of up to 30 cycles per minute. In anoptional configuration expandable diaphragm 27 may be employed toseparate the basin liquids from the primary working fluid therebyallowing a wider choice of primary working fluids, even admitting theseliquids to be the same. A means of supplying the primary working fluidto hydrodynamic modulators 72 is likewise shown in FIG. 2 and consistsof two closed containers 45 and 47 which may be pipes sized to containthe necessary volumes, a working fluid mover 49 which in most cases is apump although for gaseous fluids may be a compressor or high pressureblower, and two three-way valves, 51 and 53 which may be rotatingdirectional or solenoid activated. In operation a secondary workingfluid which may be water is pumped by working fluid mover 49 throughvalve 51 into container 47 while valve 53 prevents its discharge fromthis container. The resultant increased secondary working fluid volumewithin container 47 causes primary working fluid displacement from thecontainer into hydrodynamic modulators 72. Concurrently, secondaryworking fluid to working fluid mover 49 is supplied from container 45through valve 53 with the needed increased primary working fluid volumeto permit this secondary working fluid exit available from a second bankof hydrodynamic modulators 72 with this primary working fluid enteringcontainer 45 at port 55. The secondary and primary working fluidtraffics are then reversed by valves 51 and 53 to the alternatehydrodynamic modulator banks while working fluid mover 49 maintains asteady output.

In certain applications of the invention, solids may be formed in liquid62 which may be removed at port 50. These solids may be separated forsize by passing through a product screen, elutriator, or any such sizeclassification device 68 with the now separate product streamsdischarged through ports 69A and 69B. Also, solids removal may beaffected throughout the length of device 14 as an in-line settler orclassifer 57 can be placed betweem any port 63 and inlet 65 such thatsolids could settle and be removed via discharge 59. In other casessmall solids normally called "fines" may require destruction withanother in-line settler 61 incorporated between a port 63 and inlet 65such that liquids containing fines may be removed from the top of thein-line settler 61.

For certain applications, basin liquid recirculation may be eliminatedor minimized by incorporating liquid velocity inhibitors such as feltson partition 32. Liquids under municipal line pressure could wetpartition 32 a single time with any overflow discharged from device 14.In the same mode, all removed liquid from basin 42 may be returned tothe distributors by a single pump. Other limited flow partition methodsmay likewise be utilized, for instance the employment of capillaryaction from basins 40 and 42 following bonding of porous materials topartition 32. In these cases, as the energy content of the liquid flowis relatively small, a continual temperature segmentation may bedeveloped throughout wetted sectors 60. However, any liquid compositionchanges are more limited and ubiquitous thereby reducing theeffectiveness and energy efficiency of the invention.

Control of wetted surfaces likewise may be incorporated within ahorizontally oriented device 14. A multiple stack of chambers 34 and 36is shown in FIG. 3 incorporating a plurality of heat transfer partitions32. In this arrangement, perhaps only half of surfaces 56 or 58 ofchambers 34 and 36 may be fully wetted. Maintaining temperature andcomposition integrities of the liquid film within a horizontal chamber34 and providing migratory movement from sector to sector can beregulated by the feed rate to chambers 34 and by placement of flowdirectors on the partition. Developing channels generally perpendicularto the length of device 14 by flow directors whose height approximatesthe water film thickness maximizes retention time within each sector 60.For example, a liquid surface flow rate of 0.7 cm per minute (twice thebulk flow rate) has been observed when supplying 10 cm wide passagewaysat 100 ml per minute. In other flow director geometries, a thin filmliquid flow is directed across the width of chamber 34 where it thentravels on partition 32 through flow restrictions placed crosswise tothe length of chamber 34 to prevent liquid channeling. In general, athinner liquid film on partition 32 may be achieved with mechanicalagitation of a horizontal device 14. For example, a slightly off-centerfulcrum 39 allows revolving cam 41 to alter the slope of partitions 32in a back and forth oscillation. This action has allowed an averageliquid film depth of 0.8 millimeter to provide at least a 95 percentwetted surface on partition 32 when utilizing the four ply filmdescribed earlier. One specialized partition architecture developed forthe oscillating device includes shaded area 43 shown as an open cellfoam which provides isolation from carrier gas movement. With area 43depressed a basin in function similar to basin 40 of FIG. 2 is formedextending the chamber length. These liquid control methods may likewisebe applied to chamber 36, but with gas movement usually co-current tothe overall liquid flow.

Referring next to FIGS. 4A and 4B, an alternate configuration ofchambers 34 and 36 of device 14 is shown where the chambers arethermally connected to a separate channel set 35 containing partitions32 which provide for liquid to liquid heat transfer. Chambers 34 and 36may share a common partition 32 or the chambers may be physicallyseparated along division line 37. Partition 32 is then replaced bynonconducting walls such as walls 19 and 20 of FIG. 1 with all thermaltransfer between chambers 34 and 36 taking place by liquid to liquidheat exchange through partitions 32 of channel set 35. Gas movementoccurs only in the chambers and gas to liquid surface area may beaugmented by causing distribution means 66 and 74 to be spray deviceswhich may have upward or downward directed spray. Further, packingmaterials 39 shown as a pad in chamber 34, but may be open cell foams,rings, or other shapes may be employed in certain instances to increaseavailable surface area within a given space. Within a sector 60, liquid62 from chamber 34 is directed to channel set 35 to a second set ofdistributors 66, shwon as perforated plates, in alternate channels(illustrated as extensions of chamber 34) wetting sides 56 of partitions32. Likewise, liquid 70 of chamber 36 would be distributed in alternatechannels of channel set 35 (identified as extensions of chamber 36) bysecond distribution means 74 along partition sides 58 of partition 32.Heat transfer is accomplished by thin falling films of liquid on eachpartition side. In other heat exchange means, the channels can beflooded, thereby offering a more conventional means of liquid to liquidheat transfer such as is found in plate and frame heat exchanges. Returnof liquids to the chambers is by pumps or other liquid movement means 64and 72 from outlets 63 and 71. Migratory liquid movement between sectorsgenerally takes place in basins 40 and 42 of chambers 34 and 36, butcould be located in the channels. In FIG. 4B, a perspective view of FIG.4A, a corresponding sector 60 of device 14 and channel set 35 is shown.Describing chamber and channels 34, liquid from chamber outlet 63 isdistributed within alternate channels of channel set 35 by perforatedplates 66 wetting partition 32. In this distribution means, liquid iscontained within the channel sector by blockages 67 of plates 66 at theends of the sector. Liquid is withdrawn from channel basins via port 63which is generally centered within sector 60. Unintentional mixing ofthese basins is minimized as liquids of adjacent basins share a commondepth. In other configurations, the blockages could extend the fullheight of the channel, preventing any liquid mixing between the sectors.Liquid return to chamber 34 and control of chamber sector wetting is aspreviously described.

Referring again to FIG. 1 auxiliary heat exchange unit 15 may be anysupply or device that causes a gas stream within the initial portion ofchamber 36 to be of different temperature than the same stream leavingchamber 34. A simple supply is a feed liquid of elevated temperaturewhere upon entering chamber 34, part of its heat is transferred throughpartition 32 to the gas stream within chamber 36. In another directheating alternative, unit 15 may be a dwelling or other structure thatheats a gas stream circulating through its interior. Auxiliary heatexchange unit 15 may be a separate device as shown in FIG. 1 or may bean extension of now heat resistant and insulated walls of device 14. Gasheating may be by steam or direct flame injection when water is theprocess volatile liquid. Another type of auxiliary heat exchange unit 15may rely upon energy conversion. Solar energy may be employed where wall75 is light transmitting admitting solar energy directly upon wall 76which then radiates this energy. Provision to allow evaporation inauxiliary heat exchange unit 15 by wetting internal walls follow thosemethods described earlier. Another method for providing heat is bygas-to-gas or liquid-to-gas exchange. In one schematic using exchangingmedium 93, for example, wall 77 would act as the heat exchange surfaceincorporating provision to allow evaporation within the confines ofwalls 32 and 77. Examples of external gas include the exhaust from acombustible process, air from a dwelling, or ambien air. Examples ofliquid supply would be heated process waste stream or warm surfacewaters. In another heat exchange form, the gas stream may be changed intemperature by association with exothermic or endothermic chemicalreactions within heat exchanger 15. For example, an exothermic reactionmight include sodium metal and air or water, or heats of solution suchas dissolving potassium carbonate and water. An endothermic reactionmight be the dissolving of ammonium nitrate and water. Another deviceacting as auxiliary heat exchanger 15 for the concentration andfractionation operating modes of the invention would be compressor 94.Gas from chamber 34 would enter compressor 94 and exit at a higherpressure possessing a higher temperature. The gas would continue underpressure throughout chamber 36 and be released by flow constrictor 95,which may be a valve, turbine or orifice plate, at the chamber terminus.

Means for cooling inlet gas can be provided by supplemental gas cooler16. This unit may be separate or within the body of device 14 in theupstream part of chamber 34 with the carrier gas contacting wetted side56 of partition 32. Preferably, a separate cooler 16 is provided withthe carrier gas stream passing through chamber 78 and wetted by spray orinternal walls. Were the gas stream recycled, then utilization ofunsaturated atmospheric air as a cooling medium would require uilizationof an air-to-air exchange unit. This outside air could be chilled byspray or wetting the internal walls of chamber 79 with cooling effecttransferred through wall 80. When other gases or liquids, such as coolstream or deep ocean water, for example, are employed as the exchangemedium, cooler 16 can be any conventional gas-to-gas or liquid-to-gasheat exchange unit.

Means for moving gas through the chambers and appended to device 14where the gas is generally, but need not be, in equal flow within eachchamber is provided by gas movement unit 17. While gas movement unit 17is shown prior to supplemental gas cooler 16, location can be at anypoint in the gas path. Further, gas movement can be supplied by twounits, for instance, in dwelling air cooling or heating applications tominimize pressure change within the living space. In most operatingmodes, device 14 operates under nearly constant pressure which isdefined as the gas pressure within device 14 omitting friction loss. Inlaboratory models using narrow channels, this friction loss has beenminimal at 0.1 % pressure reduction and larger devices postulate apressure loss of less than 0.3% also at ambient pressure conditions. Gasmovement unit 17 may then be a low pressure blower or fan or other typethat delivers either a constant or pulsating gas movement.Alternatively, device 14 can be operated with greater frictional lossesusing high pressure blowers or compressors or other similar typeequipment. In cases of widely spaced chambers, such as 6 cm or more,with gas velocity of only 1 to 3 meters per minute, further gas movementcan exist within the chambers where this movement is in directions otherthan from one chamber end to the other. This movement can includenatural or forced convections caused by liquid movement on thepartition, liquid spray within the gas space, or by separate fans of lowfriction loss.

Now referring to FIG. 5, a device 14 of FIG. 1 is shown in combinationwith additional devices 14A and 14B. A gas flow director is shown asvalve 81. The devices 14 are of analogous construction except that eachdownstream device is reduced in length when compared with the firstdevice 14. While each device 14 is equipped with a gas movement unit 17Aor 17B and may be optionally equipped with a gas cooler unit, only theupstream device 14 appends to an auxiliary heat exchanger 15.

FIG. 6, a horizontal sectional view similar to FIG. 1, displays analternative embodiment of a device 14 wherein chamber 36 has beenmodified to provide for vapor or gas absorption. When device 14 isconfigured as a fractionator or stripper, and in some cases as a solidsor gel dryer, some liquid is withdrawn from basin 40 at port 50 and isdiverted by valve 86 to basin 42 via pipe 82. This liquid is generallysegregated from the remainder of basin 42 by liquid retaining wall 88 inbasin 42 and is withdrawn at port 90. When device 14 is structured as astripper with vapor absorption capability, then a portion of the liquiddiverted by valve 86 may also be diverted into basin 42 via pipe 84which alternatively may be a series of ports along basin 42. Dischargeof this liquid from basin 42 is at port 91. A less efficient method ofvapor absorption throughout chamber 36 provides for a simplified basinconstruction where liquid retaining wall 88 may be omitted. In thiscase, liquids diverted by valve 86 enter basin 42 via pipe 82 and areremoved from port 92.

Looking now to FIG. 7, a device 114 is shown in vertical side sectionalview as an alternative embodiment as a solids and gel dryer. Device 114has insulated walls 118 and 120. Partition 132 is a moving continuousbelt which may be of any suitable material and separates device 114 intotwo chambers, 134 and 136. Basin 142, running the length and width ofdevice 114, is utilized for collection of liquids present in chamber 136while side port 152 provides for liquid discharge from basin 142. Entryport and distributor 148 spreads wet gels or solids thinly and evenlyacross partition 132 while their discharge from device 114 may be bygravity, scraping, or blowing at exit 150. Ports 149 and 151 provide forentry and exit for the gas stream entering and exiting chamber 136.

Concentration, Crystallization and Purification

The invention is partially directed toward a method of liquid phaseconcentrating, crystallizing or purifying wherein, for example, a saltsolution may be further concentrated to a brine or mostly crystallinecondition while obtaining a pure distillate. Chamber 34 is segmentedlywetted throughout its length while chamber 36 may be optionallysegmentedly wetted. Partition 32 is a heat transferring chamberseparation unless both chambers are segmentedly wetted. In this case,partitions may be located externally to the chambers as described inFIG. 4A and FIG. 4B. In operation, as schematically seen in FIGS. 1 and2, a gas is caused to flow through air movement device 17 intoevaporation chamber 34. The gas may be air below ambient temperaturefollowing its subjection to a cooler 16 or may be air at ambienttemperature. The gas temperature, is raised as it evaporates vapor froma salt solution which entered basin 40 at port 48. Energy for theevaporation of the salt solution and for continued gas heating isfurnished by the opposite side 58 of partition 32 where condensationenergy is simultaneously available. Salt solution temperature andconcentration integrity is maintained by utilization of separate liquiddistribution apparati each for wetting a chamber sector 60. Saltsolution is allowed to slowly migrate counter-currently to the gas, andit eventually becomes concentrated or nearly crystallized and is thendischarged at port 50. Of course, in cases where there are minor vaporpressure differences in these salt concentrations, the feed can enter atthe cold end of chamber 34 via port 44 with the migratory flow nowco-current with the gas flow and the concentrated salt solution removedat the opposite chamber end. Following saturation at ever increasingtemperatures, the gas enters auxiliary heat exchange unit 15 where itstemperature is further raised to about ambient when a gas-to-gas heatexchange unit utilizing outside air is employed or to highertemperatures when other heat forms are used. With an increase intemperature along with sufficient evaporation from the salt solution tomaintain near saturation, the gas enters conensation chamber 36 with itstemperature elevated above that of evaporation chamber 34. The resultantcooling to temperatures above that of evaporation chamber 34, whichoccurs along the length of chamber 36 until the gas exits device 14,causes its moisture to condense. The nearly pure water condensate iscollected in basin 42 and discharged through port 52.

A concentrated solution can be further evaporated to form a saturatedsolution followed by solids production. Solids will form at a point inevaporation chamber 34 where the cooling and concentrating solution justsaturates and will continue to form throughout the remaining chamberlength. Normally, solids are removed from chamber 34 at port 50 but ifpresent may be removed upstream, for example, from an in-line settler 57via discharge 59. To aid in a selective precipitation process, materialsmay be added to basin liquids 62 at selected points. For example, abrine containing minor amounts of magnesium may precipitate magnesiumcarbonate by injecting sodium carbonate into basin liquids 62. Suchinjection within a secotr 60 may cause immediate precipitation such thata substantially pure product can be removed from chamber 34 via adischarge 59, for instance, within that same sector.

In cases where a specific size of product solids is desired, device 14may be equipped with a product screen, elutriator, or any such sizeclassifier 68 at port 50 so that preferentially larger sized solids areremoved from the classifier via port 69a and discharged. The smallercrystals, removed from port 69B, may be re-injected at a port 65 wherethe solution is saturated to remain in the system for further growth. Tocontrol small solids build-up, fines destruction may be employed wherebyclear liquid containing these fines is directed from the discharge of anin-line settler 61 located in a cooler sector 60 and re-entered into awarmer sector 60 via a port 63 where the solution is undersaturatedthereby effecting their dissolution.

In cases where the feed is highly concentrated salt there is a reductionof vapor pressure in evaporation chamber 34. This requires the gasentering chamber 36 to sensibly cool before the condensation can occur.This "dead zone" and resultant low performance factors can be partiallyovercome in two ways. The first is arranging a parallel/cascadingassembly of devices as is shown in FIG. 5. After passing throughauxiliary heat exchanger 15, a portion of the gas stream is not neededby condensation chamber 36 and is diverted by valve 81 to form asecondary gas stream. This steam is routed through condensation chamber36 of the next downstream device 14A where it is cooled in chamber 36 byan additional gas stream in evaporation chamber 34 thereof. This gasstream exits several degrees cooler than the stream entering chamber 36and is directed to condensation chamber 36 of a third device 14A.Cooling of this gas and the resultant condensation is effected by athird evaporation stream that upon passing through chamber 34 of thethird device is exhausted to the atmosphere. In the second method, acompressor 94 is usd as auxiliary heat exchanger 15. Compressor 94increases both pressure and temperature of the process gas and after itsquench, the gas returns to chamber 36 ina saturated state therebyeliminating the "dead zone" effect while using only a single heat andmass transfer device.

In another method of reconcentration utilizing evaporation from aconcentrated liquid feed stock, this feed can be caused to furtherconcentrate by intimate contact with counter-currently movingunsaturated gas. Channel 34 is utilized with the gas stream expelledfrom the system prior to auxiliary heater 15 causing partition 32 to actas any exterior wall 20. The liquid feed solution enters chamber 34 atport 48 and migrates through the chamber, exiting at port 50. Segmentedwetting of sectors 60 of chamber 34 is again employed allowing intimatevapor-liquid contact. In operation, an unsaturated gas stream propelledby gas movement unit 17 is introduced into chamber 34 and exits chamber34 in an adiabatically cooler and higher humidity state. The liquids andgases in any section 60 of chamber 34 approach vapor-liquid equilibriumso that there is a continual evaporation of liquid from the feedsolution accompanied by a continual humidification and temperaturedecrease of the gas. This evaporation, coupled with the liquid migratorymovement counter-current to the gas stream allows a continualconcentrating of the feed solution until its discharge.

Fractionation

Alternatively, device 14 can be used for fractionation wherein a morevolatile liquid is separated from a less volatile liquid. The methodfollows that described for desalination set forth above withmodification. Chambers 34 and 36 are segmentedly wetted by liquids frombasins 40 and 42 to provide intimate vapor-liquid contact. This completewetting of the chambers allows the maximum flexibility in the locationof the transferring partitions 32. Previously divided basins 40 and 42are now joined adjacent to auxiliary heat exchanger 15, and feed port 48is not located where the feed liquid phase composition closely matchesthat of basin 40.

In operation, also seen in FIGS. 1 and 2, as a gas entering evaporationchamber 34 increases in temperature (again caused by energy releasedfrom the heat of condensation upon side 58 and transferred throughpartition 32) the most volatile component of the liquid will tend toevaporate preferentially to the lesser volatile liquid species. Basins40 and 42 are each segregated as defined by segments 60, in bothchambers. As a gas moves through evaporation chamber 34 at everincreasing temperatures, it gains volatile vapors thereby depleting thevolatile species from the liquid phase. The gas, completing its passagethrough chamber 34, passes through auxiliary heat exchanger 15 andenters condensation chamber 36 at a temperature elevated above that ofevaporation chamber 34. Upon cooling, the gas phase becomes richer inthe more volatile species as, firstly, the lesser volatile speciescondenses preferentially thereby leaving the vapor phase richer in thevolatile species, and secondly, the gas phase remaining in equilibriumexperiences a richer volatile liquid phase which is movingcounter-currently to it. A rich volatile liquid phase is produced fromthe condensing vapor/gas mixture as the gas moves to exit fromcondensation chamber 36 and this condensate is discharged from basin 42via port 52, or multiple ports 52 along basin 42 if liquids or differentconcentrations are desired. In the event the gas still containssignificant volatile vapors, an absorber may be made integral withinchamber 36. As seen in FIG. 6, basin 42 is segregated by liquidretaining wall 88 into two sectors with the first and larger sector nowcontaining port 91 and functioning as above described. A portion of thestripped liquid from port 50 is diverted by valve 86 and may beoptionally cooled by any means prior to entering port 82 within thenewly formed basin. This nearly pure liquid, when distributed in chamber36, absorbs vapors from the gas thus causing is depletion thereof. Thisliquid now moving counter-currently to the gas absorbs vapors becomingricher in vapor condensate and exits chamber 36 at discharge port 90.Any heat released from this absorption is transferred to chamber 34thereby increasing the temperature of the carrier gas in chamber 34 andproviding for evaporation within chamber 34. The gas, now expelled fromdevice 14, may be released to the atmosphere or recycled first passingthrough gas movement device 17 and supplemental cooler 16 with a releaseof additional condensation at discharge 54 before entering chamber 34.Device 14 can be operated at any nearly constant pressure which isgenerally atmospheric although the pressure may be higher or lower thanambient if the device is housed within a chamber capable of withstandingthe pressure differential.

Stripper

Device 14 can be modified for use as a stripping unit as follows: First,basins 40 and 42 are again separate as depicted by FIGS. 1 and 2.Second, inlet 48 is located at the end of chamber 34 near auxiliary heatexchanger 15. Operation of device 14 as a stripper is identical tofractionation insofar as preferential evaporation of the more volatilespecies in chamber 34 is followed by preferential condensation of theless volatile species in chamber 36. However, the basin separationpreventing full counter-current liquid traffic as well as the feed inletlocation prevent enriched phase compositions within the device. Asrequired, the device 14 may incorporate the absorption modification asshown in FIG. 6 and as described for its use in fractionation.

Absorber

When separating binary mixtures composed of one highly volatile species,this volatile species tends to not readily condense within chamber 36.The separation by evaporation of the more volatile species takes placewithin chamber 34 as previously described. Chamber 36 now becomes aliquid absorber throughout its length. As seen in FIGS. 2 and 6, aportion of the stripped liquid from outlet 50 is diverted by valve 86. Afirst part of this diverted liquid is temperature adjusted to itsreceiving liquids and then injected into basin 42 via pipe 84 ormultiple pipes 84 along chamber 42. This liquid is distributed inchamber 36 and absorbs the more volatile vapors from the gas as it movestowards optional liquid retaining wall 88 and exits at port 91. A secondliquid part diverted by valve 86 may be optionally cooled prior toentering at 82. This nearly pure liquid when distributed in chamber 36and migrating counter-currently to the gas and at ever increasingtemperatures will absorb most remaining high volatile vapors from thegas. This liquid now exits basin 42 prior to wall 88 at discharge port90. The heat released from this absorption along the length of chamber36 is transferred to chamber 34 thereby continually increasing thetemperature of the gas and providing for continued evaporation withinchamber 34.

Solids or Gel Dryer

An additional function of device 14 is for solids or gel drying whereinwet solids or gels are placed in and dry solids or gels later removedfrom the evaporation chamber while the liquid evaporated is condensedand may be collected from the condensation chamber. The method followsthat described for desalination but with alterations. Chambers walls andpartitions separating the chambers are generally mounted in a nearlyhorizontal plane to facilitate adhesion of solids or gels to thepartition wall, allow for their stationary placement, as well asmaintain a solids or gel distribution of more uniform thickness. Thishorizontal partition is no longer structurally segmentedly wetted as themoisture content of wet solids or gels perform this function. Provisionis made to move the solids from one end to the other end of the devicenormally by a traveling center partition, the movement of which servesas a migratory movement.

Specifically, referring to FIG. 7, gas which is normally ambient air,enters evaporation chamber 134 while wet solids or gels are generallyplaced into the opposite or warmer end of the chamber on side 156 ofpartition 132 by distributor 148 in a thin and nearly uniform sheet. Aspartition 132 is a belt moving such that the solids or gels aretransported to exit 150, the gas and solids or gels movecounter-currently. Solids or gels and the gas become heated bycondensation energy occurring in opposite chamber 136 conducting throughpartition 132. Temperature of the solids or gels and their confinedliquids increases in a segmented manner along with the carrier gasthroughout chamber 134 with a constant shift in the vapor-liquidequilibrium between liquid and gas phases forcing moisture to evaporate.The solids or gels become increasingly drier with their migrationmovement on partition 132 and are removed from the cooler end of device114 at exit 150 containing a specified moisture content. Following itstemperature increase in evaporation chamber 134, the saturated gas flowsthrough auxiliary heat exchanger 115 where its temperature is furtherraised. The gas then enters chamber 136 via side port 149 where it,because of its elevated temperature above that of chamber 134, begins tocool with its moisture condensing upon side 158 of partition 132. Heatfrom this condensation transfers through partition 132 causing increasein gas temperature within evaporation chamber 132 and attendantevaporation. This condensate may be collected in basin 142 anddischarged from device 114 at port 152. The cooled gas exits device 114at side port 151 and is usually expelled to the atmosphere. In certaincases, the gas may contain a vapor of economic value and be flowedthrough cooler 116 to obtain further condensation of enriched liquidwhich exits by port 123. As an alternative, an integral absorbersubsystem as shown in FIG. 6 and described for fractionation andstripping may be employed.

Gas Cooling and Heating

Device 14 can also be utilized for gas cooling and dehumidification, andfor gas heating. Some gas cooling or heating operations are open cycle,while others recycle the gas stream with a heat exchange at auxiliaryheat exchange 15 and incorporate a separate heat exchanger such ascooler 16. Working fluids for open cycle methods include water or brinesacting as desiccants such as potassium carbonate, lithium halides. Inclosed cycle methods the working pairs may be at least a binary pair ofpure component materials with one material having a greater volatilitywith the materials mutually soluble. Working pairs include glycol ethersand chlorinated solvents, freons, acetone and glycerol, ethanol andcalcium chloride, water and methanol, among others. Except for gascooling without humidity modification, both channels are generallysegmentedly wetted. While this complete wetting allows flexibility inthe placement of heat transferring partitions 32, in most cases thesepartitions separate the chambers owing to the limited heat transferrequired through the partition relative to transfer in the gas to liquidinterface.

In a gas cooling mode without humidity modifications and referring toFIGS. 1 and 2, outside ambient air is brought into chamber 34 by gasmovement unit 17. Throughout most of the chamber length, for examplesectors 60 identified as 63A through 63D, the air becomes cooler bysurrendering sensible heat to a still cooler evaporation chamber 36opposite partition 32. The air stream, now cooled and generallyunsaturated, may optionally be further cooled by adiabatichumidification. This humidification may take place within chamber 34 bywetting of sector 60 location 63E or in this or the other operatingmodes may take place in a separate chamber. The air stream is injectedinto the living or storage space (auxiliary heat exchanger 15).Alternatively, in this operating mode or others a heat exchange withspace air 93 may be utilized wherein the air stream is wetted whilepassing by gas to gas heat exchange partition 77 of heat exchanger 15.Upon return the air stream, now elevated in temperature and lowered inrelative humidity, is subject to cooling by adiabatic humidificationwithin sector 60 location 71E or in this or other operating modes,separately in any evaporative cooler. The air stream, now cooler thanits opposite counterpart, is caused to gradually warm throughout thelength or chamber 36 by the energy conducting through partition 32 fromcooling chamber 34. This temperature rise is minimized by segmentedwater wetting of chamber 36 thereby providing for evaporation fromchamber 36 into the air stream and absorbing most of the energyconducted through partition 32.

In a second cooling mode incorporating humidity modification, adesiccant, which generally enters at port 48 flows counter-currently tothe air stream and exits with its absorbed water via port 63C, 63D or50. As the air continues through chamber 34, it continues to cool anddecrease its absolute and relative humidity in accordance with thedesiccant strength. In sectors dry of desiccant, air absolute humiditystays constant, while its relative humidity increases as the gas cools.Energy released by the condensation within this desiccant is conductedthrough partition 32 causing additional evaporation within chamber 36.The air stream, now cooled and unsaturated may be further cooled byadiabatic humidification and is then injected into the space. Uponreturn, the air stream now elevated in temperature and unsaturated, isprocessed as described above with segmented wetting applied throughoutthe length of chamber 36.

In a third mode of cooling a series of dehumidification andhumidifications are created to reduce a gas stream to a temperatureadequate to provide refrigeration capability. This mode may operate inopen cycle or with gas recycle then utilizing many of the working pairspreviously mentioned. In an open cycle design, ambient air enterschamber 34 and, depending on the relative humidity, may be cooled, forexample, in sector 60 location 63A, causing an increase in its relativehumidity. A desiccant stream wets sector 60 location 63B causing airstream dilution. Energy released by condensation within this desiccantis conducted through partition 32 causing evaporation within chamber 36.The still cooled air is subjected to adiabatic humidification, reducingits temperature and increasing its relative humidity as it passes bywater wetted partition sector 60 location 63C. The further chilled airis again subjected to a liquid desiccant in sector 60 location 63Dlowering its humidity. Before entering the refrigerated space the airstream may once again pass by water wetted partition at sector 60location 63E further lowering its temperature. This sequence may berepeated beyond these here described and, in most cases each functionwould transpire over a number of sectors allowing for counter-currentflow of liquids and gases. Upon return the air stream, now elevated intemperature and unsaturated, is processed as described above withsegmented wetting applied and resultant heat exchange throughout thelength of chamber 36.

In a fourth cooling mode, the device functions generally in a gasrecycle manner to provide below water freezing temperatures. The workingpairs include those discussed above. The operation follows thatdsecribed for refrigeration with the solution of lower vapor pressurereplacing the above used desiccants at locations 63B and 63D and thesolution of higher vapor pressure replacing water wetting of partitionsat locations 63C and 63E. In this recycling, device cooler 16 isemployed whereby a gas to gas heat transfer is effected through heattransfer surface 80. The secondary gas stream 93 may be taken, forexample, from a cooled inhabited space or from the refrigerationoperating mode just described.

Turning now to a gas heating mode, chamber 34 serves for evaporation andchamber 36, this time wetted with a desiccant, for condensation. Outsideambient air is brought into chamber 34 by gas movement unit 17.Throughout most or all of the chamber length, for example sectors 60identified as 63A through 63D, the chamber is segmentally wetted withwater. The air stream temperature increases receiving its energy fromcondensation occurring in chamber 36. Attendant evaporation from thewetted partition further causes vapor saturation at the ever increasingtemperatures. The air stream is then subjected to a liquid desiccantwetting at location 63E of sector 60 which causes an increase in itstemperature resulting from the energy released during the adiabaticcondensation of its moisture. After passing through the space, the airstream, now lowered in temperature and increased in relative humidity,enters chamber 36. This chamber is subjected to segmented wetting overits length with a liquid desiccant first wetting sector 60 located by71A then while absorbing water gradually flowing counter-current inbasin 42 to the air stream finally wetting sector 60 at 63E. The airstream moving through chamber 36 cools and condenses its vapor into theincreasingly concentrated desiccant with the heat released by thiscondensation transferred through partition 32.

Inhabited or storage space temperature control can be effected inseveral ways. A first preferred method is operation in on/off cyclescontrolled by a thermostat. A second preferred method involves reducingor augmenting wetted sectors by thermostat control of simple pump on/offswitches. Another method utilizes control of desiccant feed rates.Lastly, a method with more complex effects involves altering the gasrate.

Reconcentration of desiccants may take place by liquid phaseconcentration previously described or series arrangement as seen in FIG.5 or in the fractionator method. However, in areas providing periods ofwarm temperatures with reduced humidity many reconcentrations may takeplace in the cooling device using dwelling heat as auxiliary heatexchanger 15. Air is treated in chamber 34 in the manner as describedwithout humidity modification. Following return, air in chamber 36 issubjected to segmented wetting over its length with weakened liquiddesiccant first wetting sector 60 located by 71E. This desiccant whilegiving off water vapor gradually flows in basin 42 co-currently with theair stream finally wetting sector 60 at 63E. The air stream movingthrough chamber 36 first adiabatically cools then prior to its exitgradually warms while absorbing moisture from the increasinglyconcentrating desiccant. The energy for this warming and evaporation issupplied from the warmer air stream of chamber 34.

Another reconcentrating alternative is effective whenever ambient airhumidity is low enough to dehydrate the liquid desiccant to itsconcentrated level. As described previously, this separatereconcentrator uses an ambient air stream passing only through chamber34 with the reconcentrating liquids in a migration movementcounter-current to the air stream. In an alternative configuration usingthis type of reconcentrator, the desiccant may be removed from eachdesiccant wetting sector of device 14 and reconcentrated in a section ofthe reconcentrator and then returned directly to the same wettingsector.

Multiple Channel Apparatus

Now referring to FIGS. 8 through 13, a multiple channel device is shownincorporating the embodiments previously described with FIG. 8representing a perspective view. Looking now to FIG. 9, device 214comprises outside walls 219 and 220 and can be encased in additionalinsulation 230. Device 214 is divided by heat transferring partitions232 into a plurality of chambers 234 and 236 and a separate chamber 280.Assistance in maintaining the width dimension of chambers 236 and 280may be supplied by a helix of thin wire 245, such as 26 gauge stainlesssteel, spaced every 3 cm or so along their lengths. Means of gas flow tochannels 234 is supplied by duct 246 and distributed to separatechannels 234 by plenum 247. Gas collection from channels 234 is byplenum 248, generally equal in size to plenum 247, with discharge meansprovided by duct 249. Duct 249 connects to heat exchanger 15 of FIG. 1.Now turning also to FIG. 10, a sectional, view of device 214 (shown atthe termination of channels 234, 236 and 280), means of allocating thegas streams to only channels 234 is displayed. Sealing elements 250block entry to chambers 236 and 280 from plenum 247. Verticalcontainment of the gas is provided by wall 251 separating the upper andlower plenums. An identical set of sealing elements and wall are foundadjacent to plenum 248 to prevent short circuiting from chambers 234 tochambers 236.

Referring now to FIG. 11, means of gas distribution from auxiliary heatexchanger 15 to channels 236 of device 214 consists of duct 252 andplenum 253. Gas collection from channels 236 is by plenum 254 withdischarge means from device 214 provided by duct 255. Sealing elements256, also seen in FIG. 10 along with wall 251, prevent mixing of thesedischarging gases with gases of chambers 234 and sealed chamber 280while an identical arrangement at the opposite ends of chambers 234 and236 likewise prevent gas mixing.

Now referring to FIG. 12, a segregated wall wetting apparatus forchambers 234 is first shown where outlet ports 263 allow liquid movementfrom basins 240 through base wall 228 followed by connection to pump 264via pipe 269. Pumped liquids return to device 214 through pipe 270,opening 265 within wall 226 and enter chambers 234 to provide almostequal chamber flow. Distribution within channels 234 is shown bydistribution channels 266 which may be shapes that allow controlledseepage along each of their sides. A plurality of these collection,pumping and distribution apparati provide a wetting on each adjoiningpartition but maintains liquid temperature and concentration integritythrough the length of basins 240.

Looking to FIG. 13, an additional elevational plan view of device 214displays a segregated wall setting apparatus for chambers 236. Outletports 271 allow liquid collection from basins 242 and discharge to pump272 with liquid return to device 214 is via ports 273 and distributors274.

Liquids wetting and partitions of channel 34 and now channels 234 andchannel 36 and now channels 236 are in heat exchange relationship. Aportion of this heat exchange may be utilized to increase thetemperature of an incoming feed liquid. An increase in temperatureresults from energy transfer from a chamber 236 which in addition to theenergy contained in its wetting liquids generally contains heat releasedby condensation. Energy transfer is through partition 232 to a chamber280. Gas movement through this chamber is eliminated by the combinedsealing elements 250 and 256 as shown in FIG. 10. In order to transferthis heat of condensation to the feed liquids, the partition wall facingchamber 280, as shown in FIG. 13, is also segmentedly wetted throughoutits length and contains a migratory flow. In the sector so shown,liquids from basin 281 are removed via outlet port 282 and delivered bypipe 283 to pump 284. Pumped liquids are returned to device 214 throughpipe 285, wall opening 286 to enter chamber 280 and be distributedwithin the chamber segment by distribution means 287. Alternatively,channel 280 may be placed adjacent to channel 234 which normally servesfor evaporation where the energy transfer would be from the partitionwetting liquids of channel 234 to those of channel 280. Finally, in analternate channel placement of FIG. 4A heat exchange to a cooler liquidmay be along a partition separating chambers that are void of gasmovement. Two adjacent chambers or multiple pairs thereof would beclosed by sealing elements 250 and 256 while segmented partition wettingmeans as described above would remain in effect for these chambers.

Power Generation Means

Referring now to FIGS. 14 through 16, the separation capabilities of thepresent invention coupled in nearly closed cycle with reverseelectrodialysis, pressure retarded osmosis, and vapor pressuredifferential techniques are presented. The invention may be employed asa concentrator, fractionator, or stripper providing a wide choice ofworking solutions beyond brine and water mixtures normally consideredand allows for control of their concentration levels. Examples ofsolution sets, each involving a less volatile concentrate and a morevolatile condensate include brines/water, brines/alcohol and water,water/alcohol, water/ammonia, alcohols/ammonia, glycol/water orkerosine/gasoline. Solution operating temperatures can be set by heatexchange with liquids being processed by the present invention causingimproved operating efficiency.

In FIG. 14, combination with an abridged Reverse Electro-Dialysis (RED)unit is presented. RED units utilize an electrolytic solution which in anearly closed system is repeatedly diluted and reconcentrated.Concentrate 374 enters RED unit 375 and exits after passing throughcompartments 376 as diluted concentrate 377. Condensate stream 378enters compartment 379 and exits as a mixed solution 380. The internaldivisions for compartments 376 and 379 are alternately membranes 381 and382. Membrane 381 is selectively permeable to anions while membrane 382is selectively permeable to cations. In a multiple compartment unitmembranes 381 and 382 are thought of as pairs and serve to hold variousconcentrations at varying potentials. The diffusion is from theconcentrate of compartment 376 into any adjoining dilute compartment379. The anions flow one compartment to the right through membrane 381with the cations flowing likewise to the left through membrane 382. Anadditive voltage is produced across the membranes as the anions andcations permeate. The current produced, net of some process losses, isremoved at electrodes 383 and 384.

Functional separation of the solutions by the invention is identical tothat previously described. However, the device may also includeassimilation of different concentrated solutions. Solution 380 may enterchamber 334 at port 348. The more concentrated solution 377 may expel tochamber 334 at 385 where its concentration equals that of the liquidstherein. Optimum operating temperatures of liquids reaching RED unit 375may be controlled from device 314 at any basin temperature. Concentratefrom port 350 and condensate from port 352 may be heated by enteringdevice 314 and heat exchanging through means 347 and 346 with dischargeat ports 386 and 387 at the desired temperatures. From port 387 dilute378 is circulated to RED unit 375 by pump 388 while concentrate 374 isflowed from port 386 to unit 375 via pump 389.

Further heat balance may be achieved as return dilute 380 may heatexchange with device liquids by entering a port 390 flowing throughmeans 346 and exiting at port 391 with its temperature maximized priorto entry into chamber 334 via port 348. Spent concentrate 377 may enterchamber 334 at port 392 equal in temperature and heat exchanged byanother means 347 until discharged at point 385.

Referring now to FIG. 15, combination with a pressure retarded osmosis(PRO) unit is shown. Power is obtained by permeation through asemi-permeable membrane of a solution into a pressurized solutionthereby increasing its volume under pressure. Dilute solution 477, acondensate of device 414, after being heated by heat exchange withliquids of device 414 is moved by pump 478 to low pressure compartment479 of PRO device 480. A liquid of greater solute concentration 482, aconcentrate of device 414, after heat exchange with basin of device 414,is moved by pump 484 to high pressure compartment 485 of device 480. Thetwo compartments are separated by semi-permeable membrane 486. Liquidpermeates from compartment 479 into the higher concentration solute ofcompartment 485 at the higher hydraulic pressure. The resultant mixedsolution 488 exiting from compartment 485 at increased volume and aboutthe same pressure flows through unit 490 which may be a turbine, pump orturbogenerator. Effluent stream 491 is returned to device 414 at port492 and is heat exchanged until released within chamber 434 at point 493where the temperatures and concentrations of the entering and receivingliquids are nearly identical. A flushing stream 495 from compartment 479is returned to chamber 434 at port 448.

High solution concentrations with large pressure differentials arepossible by the present invention causing utilization within currentmembrane technology of a number of staged and limited differential PROunits. A stage above the system just described would utilize spentstream 491 as the dilute supplied to compartment 479 of a second PROunit while a brine of 25 to 35% concentration would be supplied fromdevice 414 to compartment 485 of a second PRO unit. The spent streamfrom this second unit could then be the concentrated brine supplied tochamber 485 of the unit first described.

Referring now to FIG. 16, a combination of the present invention with apower generation means utilizing vapor pressure differential ispresented. Looking first in a schematic side view of power cell 570, adesign utilizing vertical liquid flows, a limited series of compartmentsis shown. A more volatile solution of higher vapor pressure 571, acondensate of device 514, wets heat transmitting material 572 facingfirst compartment 573, or alternatively compartment 573 may be filledwith solution 571. A less volatile solution of lower vapor pressure 574,a concentrate of device 514, enters power cell 570 and wets heattransmitting material 572 facing second compartment 575. Vapor 576 fromthe more volatile solution 571 flows through pathway 577 across powergeneration means 580 (which may be a turbine type machine connected togenerator 581, a device involving antistatic or removal of surfacestatic charges, or other means) to compartment 575 and then condenses onheat transmitting material 572. While energy released by thiscondensation is largely transmitted to compartment 573, thistransmitting surface size is designed to cause the temperature ofcompartment 575 to be above that of compartment 573 allowing heattransfer recycle to compartment 573. Without this heat transfer, theevaporating solution will cool while warming the less volatile solutiontending then to equalize the relative vapor pressures. Temperaturestability within power cell 570 requires replenishment of energy equalto work done by power generation means 580. Heating of any fluid orvapor of cell 570 suffices where, for example, discharge stream 582 frombasin 583 flows via pump 584 through heater 585, which may employ anyrelevant heating modes described for auxiliary heater 15, and joinssolution 571 at intersect 586. The noncondensable gas within cell 570may be minimized so that internal pressures are nearly equal to thevapor pressure of solutions 571 and 574. Such degassing may take placethrough port 587 with control device 588. Combining of solutions 571 and574 to form a single vapor 576 provides a generally optimal method ofoperation when spent solution 589 collected from basin 590 is relativelysimilar to solution 574, a condition that generally implies solution 574being in greater volume than solution 571. In cases where solutionvolumes 571 and 574 are more closely related so that a more rapidconcentrational change in spent solution 589 relative to solutions 571and 574 is evidenced, a greater power output may be obtained by stagingthe combining of these solutions. Such staging requires a multiple setof power cells 570 where spent solution 589 becomes either solution 571or 574 of a subsequent cell.

Where the operating temperature of power cell 570 is approximately thesame as the highest liquid temperature of device 514 all thermalenergies required for device 514 may be efficiently supplied by heater585. Spent solution 589 may then supply heat for device 514 entering atport 548 and then transferring its heat from chamber 534 to 536. Theconcentrate from port 550 and the condensate from port 252 may beincreased in temperature by heat exchanging with liquids of device 514utilizing heat exchanger means 546 and 547. Discharge at ports 590 and591 would be at the highest available temperature. From port 590solution 574 is circulated to power cell 570 by pump 592 while solution571 is flowed from port 591 to power cell 570 via pump 593. Partialenergy requirements for pumps 591 and 593 may be met by affixing powerrecovery pump 594 to spent solution 589. In cases where the operatingtemperature of power cell 570 is different from that of device 514,additional heat exchanger 595 may be employed to either increase ordecrease these temperatures.

EXAMPLES

The present invention is more particularly described and explained bymeans of the following Examples. These are intended only to illustratethe invention and are not to be construed to limit the scope of theinvention.

Experimental data reported herein was obtained from a device similar tothe schematic of FIGS. 1 and 2, measuring 3 meters in length and 0.6meters in height. The heat transferring partition was the wovenpolyethylene film previously described. Chamber width was variable from3 mm to 13 mm (typically 3 mm). Partition wetting was segmented intofive sectors with wetting from basin liquids available to either or bothpartition sides (with partition side 56 normally wetted) and migratorymovement provided by basins similar to basins 40 and 42. Auxiliary heatwas generally by direct steam injection except for air cooling andliquid desiccant experiments. Primary gas temperature measurements weretaken at locations delineated as "T1" (gas entrance), "T2" (end ofchamber 34), "T3" (chamber 36 beyond heat exchanger 15), and "T4" (gasexit). Liquid basin temperatures and concentrations were measured withinsectors identified by 63A-E and 71A-E. Applicable performance factorswere developed by dividing energy supplied by the steam generatoradjusted for known device heat losses.

EXAMPLE I

In a desalination experiment, a weak brackish solution feed wasfurnished to the device at 100 milliliters per minute to obtain deviceperformance. Air was supplied at a 0.06 cubic meters per minute rate (agas velocity of 55 cm per second). Steam was set to provide atemperature of approximately 80° C. at T3. The results are as follows:

    ______________________________________                                        Steam Usage         0.23 kg per hour                                          ______________________________________                                        T1                  14° C.                                             T2                  77° C.                                             T3                  79° C.                                             T4                  34° C.                                             Condensate rate     33 ml per minute                                          Performance factor  8                                                         ______________________________________                                    

EXAMPLE II

An experiment was conducted to ascertain the wetting liquid temperatureprofile throughout chamber 34. Gas temperature was 73° C. at T3. Theprofile at steady operation is:

    ______________________________________                                        1. 63E - near heat exchanger 15                                                                    71° C.                                            2. 63D               62° C.                                            3. 63C               54° C.                                            4. 63B               44° C.                                            5. 63A - near drain  36° C.                                            ______________________________________                                    

EXAMPLE III

A liquid containing commercially available sea salt with a specificgravity of 1.025 was supplied to determine a developed concentrationdensity profile when utilizing segmented wetting and migratory movement.The results obtained are:

    ______________________________________                                                         Specific Gravity                                             ______________________________________                                        1 63E - near auxiliary heater                                                                    1.065                                                      2 63D              1.074                                                      3 63C              1.091                                                      4 63B              1.096                                                      5 63A - near condensate drain                                                                    1.099                                                      Drain              1.105                                                      Condensate         0.993                                                      ______________________________________                                    

EXAMPLE IV

A potassium carbonate solution feed with a specific gravity of 1.24 wasfurnished at 85 milliliters per minute to obtain air temperatures andliquid concentrations. Air was supplied at the rate of 0.34 cubic metersper minute. Steam provided a temperature of approximately 71° C. at T3.The results obtained are as follows:

    ______________________________________                                        Steam Usage           1.8 kg per hour                                         ______________________________________                                        T1                    42° C.                                           T2                    72° C.                                           T3                    73° C.                                           T4                    49° C.                                           Condensate rate       52 ml per minute                                        Condensate - specific gravity                                                                       1.001.                                                  Drain discharge rate  32 ml per minute                                        Drain liquid - specific gravity                                                                     1.51 (contained                                                               potash crystals)                                        ______________________________________                                    

EXAMPLE V

The device was adjusted for the fractionator function with bothpartition sides segmentedly wetted and chamber 34 and 36 basins combinedadjacent to the heater. An inline blower and a supplemental cooler (agas to liquid heat exchanger) were supplied. The gas (a combination ofnitrogen and air) was supplied at a 0.34 cubic meters per minute rate.Feed was a 10 volume % ethanol and water mixture injected adjacent tothe heater at 75 milliliters per minute. The results were as follows:

    ______________________________________                                        Steam rate            0.15 kg per hour                                        ______________________________________                                        T1                    27° C.                                           T2                    44° C.                                           T3                    46° C.                                           T4                    28° C.                                           Concentrations (ethanol)                                                      1. 63A                2%                                                      2. 63C                7%                                                      3. 63E - near heater  9%                                                      4. 71E - near heater  10%                                                     5. 71C                12%                                                     6. 71A                16%                                                     Condensate at cooler  41%                                                     (Partial condensation)                                                        Energy requirements per liter                                                                       93 kcal                                                 of 41% ethanol                                                                ______________________________________                                    

EXAMPLE VI

The device was next modified as an air cooler with partition wettingchanged to chamber 36. Chamber widths were adjusted to 6 mm. The airstream passing through chamber 34 was cooled by the same stream passingthrough chamber 36. For comparison, the device was adjusted to functionas an evaporative cooler such that air moving through chamber 34 wassubject to liquid contact by wetting of side 56 of chamber 34 withchamber 36 unutilized. The air stream was at 46 degrees C and itsrelative humidity 27%. The results are tabulated below.

    ______________________________________                                                              Relative                                                             Temperature                                                                            Humidity                                                ______________________________________                                        Air Cooler                                                                    1. 63A         36° C.                                                  2. 63C         33° C.                                                  3. 63E         29° C.                                                                            61%                                                 4. 71E         25° C.                                                                            88%                                                 5. 71C         31° C.                                                  6. 71A         31° C.                                                                            80%                                                 Swamp Cooler                                                                  1. 63A         31° C.                                                  2. 63C         30° C.                                                  3. 63E         29° C.                                                                            100%                                                ______________________________________                                    

Both devices reduced the air stream to 29° C. at position 63E howeverthe relative humidity was 61% for the air cooler versus saturation forthe swamp cooler. At full saturation the air temperature of the aircooler would have been 22° C. at location 63e of some 7° C. cooler thanthat possible with the swamp cooler.

EXAMPLE VII

A 50% solution of potassium carbonate and water was utilized as a liquiddesiccant to lower adiabatically the relative humidity and increase thetemperature of an air stream. Only chamber 34 was used and the partitionwas segmentedly wetted with the desiccant migrating counter-currently tothe air stream. Air supplied was at 25° C. adjusted to near saturation.The air stream temperatures and humidity modification are presentedbelow.

    ______________________________________                                        1. 63A - near air inlet                                                                         25° C.                                               2. 63C            32° C.                                               3. 63D            33° C.                                               4. 63E            33° C.                                               Relative Humidity 56%                                                         ______________________________________                                    

EXAMPLE VIII

A device with a daily design capacity of 378,540 liters of waterdistillate utilizing solar thermal energy is developed assuming averagearid ambient air temperature of 27° C. and average relative humidity of30%. A sea water feed is assumed to concentrate 4 times. Alternately, abrackish water feed of 3,000 parts per million total dissolved solidswould be reduced 50 times. Using 82° C. as maximum device temperatureand an eight hour solar day, a transfer area of 38,461 square meterswould be required. Inexpensive plastic film would be segregated into1,725 6.25 millimeter wide channels dimensioned 1.83 meters high by 12.2meters long. The device thermal performance factor is slightly over 40.The flat plate collector field would approximate 1,700 square metersbased on an hourly solar incidence of 67.8 calories per squarecentimeter and 54% energy conversion. Air movement totals 868 cubicmeters per minute with a static pressure of 12.7 millimeters watercolumn. Computed power requirements are 1.76 kilowatts (kw) and withfans operating at a 48% efficiency requires 3.7 kw. Segregated modulatedpumping requirements for wetting partitions in alternate chambers at 60%efficiency causes power consumption of 2.0 kw. Total electrical usageequals 0.12 kwh per cubic meter of distillate. In comparison, a recentstudy found reverse osmosis procedures have an electrical usage of 2.09kwh per cubic meter.

Utilizing direct injected natural gas for heat, 24 hour operation wouldallow device size reduction of two-thirds. Daily parasitic powerrequirements (46 kwh) would stay equal while gas usage would be 1.44cubic metrs per cubic meter of distillate. Thermal requirements are then12,800 kilo calories per cubic meter of distillate. A recent comparativestudy found vertical tube evaporation and multistage flash processeswith respective requirements of 47,100 and 55,500 kilo calories percubic meter of distillate. This study also developed capital cost forbrackish water distillation plants. The present invention may cost aboutone-fifth of a VTE plant and under one-third of a reverse osmosis plantwith evaporation ponds.

EXAMPLE IX

Requirements for distillation of 4,536 kilograms per hour of 10 weight %ethanol and water into 594 liters of a 95 weight % distillate stream anda water stream are developed. The fractionator would contain 344 squaremeters of transfer area divided into 120 chambers 4.66 meters long by0.61 meters high. The air supply would be 17 cubic meters per minute of27° C. 30% relative humidity air that would first be cooled to 16° C. byadiabatic humidification. This air stream would reach 82° at theauxiliary heater with an energy requirement of 25,200 kilo colories perhour. This air stream would then cool to 21° C. for atmosphericdischarge. Computed electrical usage for air movement and liquid pumpingis 0.35 kw and adjusted to 1.23 kw to reflect mechanical and electricalinefficiencies. The device would consume 9.8 liters per hour of water byevaporation into the exhaust air. Thermal energy requirements could bemet by 69 square meters of solar collector of Example VIII, or by 0.036cubic meters per minute of natural gas direct heat injection. Energyneeded per gallon of 95% ethanol distillate would be 44.2 kilo caloriesper liter or 664 Btu's per gallon.

EXAMPLE X

A device capable of meeting dwelling comfort zone requirements of 24° C.and under 65% relative humidity for summer and 20° C. during the winteris developed. Climatic conditions selected include an arid area(Phoenix, Arizona) with a summer design specification of 42° C. dry bulband 22° C. wet bulb and a January minimum normal temperature average ofnearly 4° C. dry bulb. A second area for cooling evaluation is hot andcontinually very humid Houston, Texas with design parameters of 35° C.cry bulb and 25° C. wet bulb. Summer load requirements are specified at3 tons (36,000 Btu's or 9,072 kilo calories) with a latent heat factorequal to 30% of the total load. The device would contain 37 to 93 squaremeters of transfer partition depending upon channel configuration. Airmovement would be 62 cubic meters per minute. System pressure (7.9millimeters for the device plus external spray adiabatic activities andair duct resistances) is 1.3 cm water gage. Maximum system computed airmovement requirements are 0.13 kw. or 0.325 kw at a 40% blowerefficiency. Utilizing spray nozzles, pulsed chamber wetting requires 53liters per minute and at 20% efficiency (hydrodynamic modulating system)electrical power including adiabatic wettings would be 0.125 kw. Maximumpower use is 0.325 kw (279 kilocalories per hour). Function at variousclimatic parameters is projected below.

EXAMPLE XA

During arid area cooling operation, ambient air entering the firstchamber is cooled by heat transfer through the partition to 18° C. andfurther adiabatically cooled to 14° C. for dwelling injection. Uponreturning the 24° C., 55% relative humidity air is adiabatically cooledto 17° C. and sujected to partition segmented wetting and exits at 24°C. saturated. Water usage is 20 liters per hour. As the system hasexcess capacity, the fraction of time in use (operating factor) is 54%resulting in utilization of 0.24 kw of 209 kilo calories per hour orelectrical coefficient of performance (COP) of 43. In comparison, astandard heat pump producing the same cooling energy generally has a COPof 2.0 to 2.5.

The effect of nonsegmentation of partition wetting has been simulatedusing the above design criteria and device. Air temperature to thedwelling would be 18° C. versus 14° C. and the dwelling would establisha 70% relative humidity compared with 55%. Cooling capacity would be 61%of the segmented wetting approach.

To meet the same dwelling design temperture of 24° C. an evaporative"swamp" cooler would utilize 142 cubic meters of air per minute. Waterconsumption would be 81 liters of water per hour, however, relativehumidity in the dwelling would reach 89%, a condition far outsideaccepted comfort zone standards.

EXAMPLE XB

In cooling the humid area, ambient air entering the first chamber iscooled by thermal transfer through the partition to 24° C. and 85%relative humidity. In its relative humidity would then be reduced to 50%using a liquid desiccant such as a 50 weight % solution of potassiumcarbonate at the rate of 16 kilograms per hour. Water removed totals 37kilograms per hour causing a dilution in the desiccant to 15 weight %.The 24° C. and 50% relative humidity air is then adiabatically cooled bythe spent desiccant stream to 19° C. and 85% relative humidityevaporating 9.5 kilograms of water per hour. The air is dwellingcirculated and returned at 24° C. and 64% relative humidity. The air isadiabatically cooled to 19° C. and continuously wetted in the secondchamber exiting saturated at 26° C. Water usage totals 45 liters perhour and a net 44 kilograms per hour of 18% desiccant solution wouldrequire reconcentration. System electrical usage would be 0.45 kw (388kilo calories per hour) resulting in an electrical COP of 23.

EXAMPLE XC

During arid area winter conditions, heated air may be supplied where 4°C. ambient air is brought into the first chamber with its partitionsegmentedly wetted with water. Absorbing heat through the partition, theair stream heats to 15° C. devleoping a nearly saturated condition. Atemperature increase to 22° C. is then affected by dehumidifying the airto 50% relative humidity by exposure to a 50 weight % solution ofpotassium carbonate removing 15 liters of water per hour. The heated airenters the dwelling and returns to the other chamber at 20° C. and 58%relative humidity and is increased in humidity by adiabatic cooling.This chamber is segmentedly wetted with the desiccant entering at fullstrength at the chamber exit and slowly flowing counter-currently to theair stream. Owing to heat transfer through the partition, the air streamcools and exits at 7° C. and 50% relative humidity having lost watervapor (30 liters per hour) throughout its path. Desiccant usage totals23 liters per hour and is diluted to 10% in the first dehumidificationand to 30% in the second chamber. The electrical COP in this functionwould be 5.9. By comparison, a standard heat pump operating in a heatingmode at these design parameters has a COP of slightly over 2.5.

EXAMPLE XI

Methods for concentrated salt regeneration are developed for highhumidity areas (Houston, Texas). The potassium carbonate solution ofExample XB would be concentrated from 18% to a 50% in the parallelcascade device arrangement. Ambient air in the first device would beheated from 35° to 82° C. in the evaporating chamber and cool to 38° C.in the concentration chamber. A portion of the air stream, some 24%which is in excess of energy balance requirements of the first device,would be diverted to a second device before entering the condensingchamber with this cascade effect repeated throughout the device stack.Nine devices with partition area of 26 square meters are utilizedranging in size from 8.2 to 0.6 square meters. The air rate is 1.5 cubicmeters per minute with the first device receiving 0.36 and the ninth0.10 cubic meters. Thermal energy requirements would total 1,850kilocalories per hour giving a performance factor of 7.2.

As an alternative method of desiccant regeneration, a compressor may beused with a single device. Assuming the same ambient conditions andtemperature rise in the evaporation chamber, the air stream would becompressed to 20 kPa with its temperature increased to 105° C. Followingsaturation, the air stream would enter the condensation chamber at 85°C. and exit and be pressure relieved at 54° C. Regenerating the sameflow of desiccant, the device would require 13.3 square meters oftransfer surface with air movement of 1.5 cubic meters per minute.Thermal requirements total 660 kilocalories or an electrical powerconsumption (at 50% efficiency) of 1.52 kw providing an effectiveperformance factor of 10.

In a third method of desiccant regeneration, a device using onlyevaporation chambers can be employed. A suitability sized device, forexample, with air movement of 142 cubic meters per minutecounter-current to the liquid migratory flow would provide the samewater removal rate of 23.5 liters per hour.

EXAMPLE XII

A small scale electrical plant is developed with a vapor pressuredifferential power cell combined with the ethanol and water productsfrom Example IX. The fractionator hourly streams of 594 liters of 95%ethanol and 4,060 kilograms of water at 18° C. would first be reroutedthrough the device absorbing the feed stock energy. These heated streamswould be pumped to opposite sides of a 15 square meter power cell heatexchanger. The ethanol stream would be controlled to 79° C. in the 106kPa evaporation compartment while the water side of the cell would bemaintained at 82° C. Evaporating ethanol vapors would pass through aturbine or low pressure blower utilizing 6 PSI pressure drop producing4.4 kw of electrical energy (omitting turbine losses). These vaporswould then condense in the water compartment at 65 kPa giving up theenergies of condensation which conduct through the heat exchanger wallto the cooler evaporation compartment. The 10% ethanol solution formedin the 82° C. condensation compartment would be returned to thefractionator as the hot feed stock thus completing the cycle. Operationand temperature ranges of the fractionator as well as its size (344square meters) and air traffic (17 cubic meters per minute) would be thesame as previously described. The heat exchange area for reheating theproduct streams would total 139 square meters generally of inexpensiveplastic film material or stainless steel foil.

What is claimed is:
 1. Apparatus for changing at least one selectedproperty of two wetting substances, said apparatus comprising:a firstchamber containing a plurality of sectors; first wetting means forsegmentedly wetting substantially all of said sectors with a firstsubstance; migration means coupled to said first wetting means forproviding a migratory movement for said first substance between adjacentsectors; a second chamber containing a second plurality of sectors;second wetting means for segmentedly wetting substantially all of saidsectors of said second chamber with a second substance; gas means forcontrolling a flow of gas through said segmentedly wetted chambers,wherein said gas flow in said first chamber and said second chamber iscounter-current; a heat transferring partition thermally connecting saidfirst and second chambers, wherein sectors in said first chamber andsaid second sector are bounded by said heat transferring partition;temperature means for changing a temperature of said gas during a flowbetween said first and second chambers, said changing of temperatureresulting in transfer of heat between said first and second chambersthrough said partition between said first substance and said secondsubstance, wherein a temperature of said first substance and atemperature of said second substance are respectively below a boilingtemperature for each substance during substance wetting, whereininteraction in said sectors between said substances and said gas causesa change in at least one selected property of said first and secondsubstances, said gas approaching a vapor-liquid equilibrium with saidsubstances for each of said wetted sectors, wherein interaction by saidfirst substance and said migratory movement causes said selectedproperty of said first substance of a sector to influence said selectedproperty of said first substance in an adjacent sector.
 2. The apparatusfor changing at least one selected property of claim 1 wherein saidselected property is a substance temperature.
 3. The apparatus of claim1 wherein said selected property is a substance composition.
 4. Theapparatus for changing at least one selected property of claim 1 furthercomprising a second migration means coupled to said second wetting meansfor providing a second migratory movement of said second substance,wherein interaction between said second substance and said secondmigratory movement causes a selected property of said second substanceof a sector to influence said selected second substance property in anadjacent sector.
 5. The apparatus for changing at least one selectedproperty of claim 4 further comprising flow control means fortransferring a portion of said migratory flow substance between saidfirst and said second chambers.
 6. The apparatus for changing at leastone selected property of claim 1 further including heat exchange meansfor providing heat exchange between at least one of said substances andsaid first substance prior to introduction of said first substance intosaid first chamber.
 7. The apparatus for changing at least one selectedproperty of claim 1 further comprising cooling means for cooling saidgas prior to introduction into said first chamber.
 8. An apparatus forheat and mass transfer comprising:a heat transferring partition; a firstchamber having a first surface of said partition as a first chamberboundary; first wetting means for segmented wetting of at least part ofsaid first surface by a first wetting substance; first migratory flowmeans coupled to said first wetting means for providing a migratory flowof said first wetting substance; a second chamber having a secondsurface of said partition as a second chamber boundary, said secondchamber thermally coupled to said first chamber by said heattransferring partition; second wetting means for segmented wetting of atleast part of said second surface by a second wetting substance; secondmigratory flow means coupled to said wetting means for providing amigratory movement of said second wetting substance in said secondchamber; gas means for regulating a flow of gas causing said gas to flowthrough said first and said second chambers, wherein said gas flow ineach chamber is counter-current; and thermal means for changing atemperature of said gas flowing between said first chamber and saidsecond chamber, said thermal means causing a temperature differencebetween said first and said second chamber permitting heat transferbetween said first wetting substance and said second wetting substancethrough said heat transferring partition and mass transfer between saidfirst wetting substance and said gas and between said second wettingsubstance and said gas, wherein said gas approaches a vapor-liquidequilibrium with each wetting substance in each segment of saidsegmentedly wetted surfaces, a heat provided by said thermal means isless than a heat transferred through said heat transferring partition.9. The apparatus for heat and mass transfer of claim 8 wherein said masstransfer is a result of evaporation from said wetting substance.
 10. Theapparatus for heat and mass transfer of claim 8 wherein said masstransfer is a result of condensation into a wetting substance.
 11. Theapparatus for heat and mass transfer of claim 8 further comprising heatexchange means for providing heat exchange between at least one of saidsubstances and said first substance prior to introduction of said firstsubstance into said first chamber.
 12. The apparatus for heat and masstransfer of claim 8 further comprising flow control means fortransferring at least a portion of said migratory substances betweensaid first and said second chambers.
 13. The apparatus for heat and masstransfer of claim 8 wherein pulsed wetting is provided by hydrodynamicmodulators comprising an enclosure with sufficient ports and checkvalves so that an increase in primary working fluid volume within saidenclosure displaces at least a portion of said liquids therein andcauses said displaced liquids to flow into said chambers, saiddisplacement followed by a time interval wherein said primary workingfluid volume decreases, said decrease allowing said liquids from saidchambers to enter said enclosure.
 14. The apparatus for heat and masstransfer of claim 13 wherein the apparatus for supplying said primaryworking fluid volume to said hydrodynamic modulators includes two closedcontainers, a working fluid mover, and valves with timing devices,whereby said working fluid mover operates by moving a secondary workingfluid to one container and displacing residual primary working fluidtherefrom while receiving its secondary working fluid from an othercontainer, said other container having means for receiving primaryworking fluid to allow for said secondary working fluid displacement andfor causing said secondary working fluid and primary working fluidtraffic to reverse flow direction.
 15. Apparatus for heat and masstransfer, said apparatus comprising:a heat transferring partition; afirst chamber having a first surface of said partition as a firstchamber boundary; first wetting means for segmented wetting at leastpart of said first surface with a first wetting substance, wherein atemperature of said first wetting substance is below a boilingtemperature of said first wetting substance; first migratory flow meanscoupled to said first wetting means for providing a migratory flow ofsaid first wetting substance; a second chamber having a second surfaceof said partition as a boundary, said second chamber thermally coupledto said first chamber by said heat transferring partition; secondwetting means for segmented wetting of at least a portion of said secondsurface by a second wetting substance, wherein a temperature of saidsecond wetting substance is below a boiling temperature of said secondwetting substance; gas means for causing a gas to flow through saidfirst and said second chambers, wherein said gas flow in each chamber iscounter-current, said gas having a substantially constant pressure insaid apparatus; and thermal means for changing a temperature of said gasflowing between said first chamber and said second chamber, said thermalmeans causing a temperature difference between said first and saidsecond chamber permitting heat transfer between said first wettingsubstance and said second wetting substance through said heattransferring partition and mass transfer between said first wettingsubstance and said gas and between said second wetting substance andsaid gas, wherein said gas approaches a vapor-liquid equilibrium witheach said wetting substance in each segment of said segmentedly wettedsurfaces, heat provided by said thermal means being less than heattransferred through said heat transferring partition.